// pages/catering.js
Page({
 
    /**
     * 页面的初始数据
     */
    data: {
      tabs: [
        { title: '特惠', anchor: 'a', },
        { title: '必点', anchor: 'b', },
        { title: '营养汤', anchor: 'c', },
        { title: '主食', anchor: 'd', },
        { title: '套餐', anchor: 'e', },
        { title: '饮料', anchor: 'f', },
      ],
      tabsList: {
        a: [{
          price: 10.1, anchor: "a", index: 0, num: 0
        }, {
          price: 10.2, anchor: "a", index: 1, num: 0
        },
        {
          price: 10.3, anchor: "a", index: 2, num: 0
        },],
        b: [{
          price: 10.4, anchor: "b", index: 0, num: 0
        }, {
          price: 10.5, anchor: "b", index: 1, num: 0
        },
        {
          price: 10.6, anchor: "b", index: 2, num: 0
        },],
        c: [{
          price: 10.7, anchor: "c", index: 0, num: 0
        }, {
          price: 10.8, anchor: "c", index: 1, num: 0
        },
        {
          price: 10.9, anchor: "c", index: 2, num: 0
        },],
        d: [{
          price: 11.0, anchor: "d", index: 0, num: 0
        }, {
          price: 11.1, anchor: "d", index: 1, num: 0
        },
        {
          price: 11.2, anchor: "d", index: 2, num: 0
        },],
        e: [{
          price: 11.3, anchor: "e", index: 0, num: 0
        }, {
          price: 11.4, anchor: "e", index: 1, num: 0
        },
        {
          price: 11.5, anchor: "e", index: 2, num: 0
        },],
        f: [{
          price: 11.6, anchor: "f", index: 0, num: 0
        }, {
          price: 11.7, anchor: "f", index: 1, num: 0
        },
        {
          price: 11.8, anchor: "f", index: 2, num: 0
        },]
      },
        indexId: 0,
      toTitle:"title-c",
      scrollTop:0,
      top:[],
      },
      // 左侧点击事件
      jumpIndex(e) {
        let index = e.currentTarget.dataset.menuindex;
        let anchor = e.currentTarget.dataset.anchor;
        let that = this
        that.setData({
          indexId: index,
          toTitle: "title-" + anchor
        });
        //可以设置定位事件
     
      },
   
    scrollToLeft(res){
      console.log("scrollToLeft-res:" + JSON.stringify(res) + JSON.stringify(this.data.top));
      // let top=res.detail.scrollTop;
      this.setData({
        scrollTop: res.detail.scrollTop
      })
      var length = this.data.top.length;
      for(var i=0;i<this.data.top.length;i++){
        if (this.data.top[i] - this.data.top[0] <= this.data.scrollTop && (i < length - 1 && this.data.top[i + 1] - this.data.top[0] > this.data.scrollTop)){
         if(this.data.indexId!=i){
            this.setData({
              indexId: i,
            }); 
          }
        }
      }
      // console.log("top:"+top);
    },
   
      /**
       * 生命周期函数--监听页面加载
       */
      onLoad: function (options) {
        var that = this
        wx.getSystemInfo({
          success: function (res) {
            that.setData({
              winHeight: res.windowHeight
            });
            var top2=new Array();
            for(var i=0;i<that.data.tabs.length;i++){
              wx.createSelectorQuery().select('#view-' + that.data.tabs[i].anchor).boundingClientRect(function (rect) {
               
                var isTop=Number(rect.top);
               
                top2.push(isTop);
                console.log("view-c:" + JSON.stringify(rect));
                
              }).exec();
              
            }  
            that.setData({
              top: top2
            });
          }
          
        });
        
      },
   
  })